JP2500354B2 - Flocculant - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to flocculation and flocculation of flocculation and flocculation of suspension water, coloring water and other aqueous liquids, sedimentation and flotation of flocs (including flotation with bubbles on particles). The present invention relates to an aggregating agent used for the purpose of screening, concentration of an aqueous liquid by filtration, dehydration and clarification.

The coagulant according to the present invention settles in water treatment such as water treatment, industrial water treatment, industrial wastewater treatment, sewage treatment, wastewater treatment such as human waste treatment, various production processes in agriculture, mining and industry, etc. , Flotation, screening, separation / concentration of suspended substances and solutes contained in suspension / colored water and other aqueous liquids by filtration, dehydration, flocculation for clarifying the aqueous liquid (including flocculation, precipitation formation), It is used for the purpose of increasing the papermaking speed and improving the yield in the papermaking process due to aggregation.

[0003]

2. Description of the Related Art Aggregation (floc formation) of suspended water, colored water, and other aqueous liquids separates suspensions (colloidal particles, coarse particles, etc.) contained in the aqueous liquid and certain solutes as flocs. For solute precipitation and flocculation of colloidal particles, coarse particles, etc.
It is widely used for solid-liquid separation by screening, filtration (clarification filtration, dehydration filtration) and the like.

Conventionally, as an aggregating agent used for such an aggregating purpose, an inorganic salt such as an aluminum salt or an iron salt,
Alkali such as sodium hydroxide or calcium hydroxide,
Acids such as sulfuric acid and hydrochloric acid, sodium silicate, ionic surfactants, water-soluble natural polymer starch, protein, sodium alginate, chitosan, synthetic polymer polyacrylamide, sodium polyacrylate,
Polyacrylic acid dialkylaminoethyl ester salt, polymethacrylic acid dialkylaminoethyl ester salt, aniline resin hydrochloride, polythiourea hydrochloride, polyethyleneimine, aliphatic polyamine-epihalohydrin polycondensate, etc. are known, but especially Cationic ones have a small hydrophobic group (eg vinyl, polyethyleneimine), and those with a high degree of polymerization have a graft / crosslinking bond.
A linear polymer having a large degree of polymerization and being stretchable and expandable, that is, a polymer having a significantly low aggregating value (the minimum required concentration of a drug necessary for rapidly aggregating an aqueous liquid) and having a large crosslinking and adsorbing action, That is, no flocculant has been produced that forms large stable flocs.

In particular, a cationic polymer electrolyte is widely used for dehydration of surplus sludge, but a large amount is used, and a flocculant that forms a stable floc that is effective even at a small amount is developed. Is desired.

The present invention seeks to develop an effective flocculant having a higher degree of polymerization and a cationic linear polymer as a flocculant for a suspension.

Conventionally, as the cationic polymer electrolyte, acrylic acid dialkylaminoethyl ester-based ones, methacrylic acid dimethylaminoethyl ester-based ones, polyethyleneimine, chitosan, various polycondensates and the like are known.

[0008]

Polymerization type acrylic acid dialkylaminoethyl ester type and methacrylic acid dimethylaminoethyl ester type ones having a slightly high degree of polymerization are obtained, and they are widely used. However, when the degree of polymerization is increased, a graft reaction and a cross-linking reaction occur, and a high degree of polymerization and high performance have not been obtained.

Although Mannich modified products of polyacrylamide have a high degree of polymerization, many have a low degree of cation modification.

Water-soluble polyethyleneimine and chitosan have a low degree of polycondensation and have not been obtained with high aggregation performance.

The inventors of the present application are polycondensation type, and for the purpose of obtaining a polycondensation type having a high degree of polymerization and a high aggregation performance, a polycondensation product of an amino compound and an aldehyde such as formaldehyde, glyoxal or glutaraldehyde, ammonia or amino. I have been studying polycondensates of compounds with epihalohydrin, especially polycondensates of 4-aminomethyl-1,8-octanediamine with epihalohydrin at a molar ratio of about 1: 1.
Furthermore, by the method of reacting with dialdehyde under appropriate conditions,
A cationic polycondensate with a high degree of polycondensation was synthesized, and the results of aggregation experiments revealed that it had remarkable aggregation performance.

[0012]

Based on the above findings, the present invention differs from conventional flocculants in that the molar ratio of water-soluble 4-aminomethyl-1,8-octanediamine to epihalohydrin is about 1: 1. Dialdehyde in the polycondensate of, the molar ratio per 4-aminomethyl-1,8-octanediamine of the raw material
A novel flocculant comprising a water-soluble high polycondensate or a salt thereof obtained by adding and reacting within the range of 1: 0.0001 or more is proposed.

The coagulant according to the present invention has a remarkably large degree of polymerization, is highly expandable and expandable, has a small intramolecular loss of the active group, has a reaction activity and an adsorption activity, and has a large hydrophobic group.
It forms a large and stable floc with a small aggregation value,
Therefore, in particular, turbidity / color removal of suspended water / colored water, and sedimentation promotion, flotation promotion, filtration promotion, improvement of concentration / dehydration due to agglomeration of colloidal substances and coarse particles, reduction of COD by them,
Anionic substances (eg alkylbenzene sulfonic acid,
It has been found that it has a remarkable effect on removal of phosphoric acid, silica, etc., speedup of papermaking in the papermaking process, strengthening of paper strength and the like.

Water-soluble 4-aminomethyl according to the present invention
A water-soluble high-polycondensate obtained by reacting a 1,8-octanediamine-epihalohydrin polycondensate with a dialdehyde is basically a linear or nearly linear stretchable / expandable high-condensate. It is a condensate.

Currently known water-soluble, cationic, high-polymerization polymeric substances have a graft bond or a cross-linking bond, and those having a particularly high viscosity have a reticulated structure and are on the verge of jellying. Since the amine group is in the network structure or inside the contracting molecule and the active groups are lost, even if dialdehyde is added to them and reacted, almost no improvement in performance is observed, rather the performance decreases. To do.

4-aminomethyl-1,8-octanediamine-epihalohydrin polycondensate, which is 4-aminomethyl-1,8
-Equimolar amounts of octanediamine and epihalohydrin, or the reaction products before and after that (molar ratio 1: 0.8 to 1.1 are preferable), are linear polycondensates with slightly high viscosity, which can be obtained by known methods. Is synthesized.

The invention is based on the fact that when they are further reacted with dialdehydes, they are obtained with outstanding flocculation performance not heretofore obtained.

4-aminomethyl-1,8-octaneamine-
Reacting an epihalohydrin polycondensate with a dialdehyde,
Conditions for producing a high-performance, high-condensation product that is water-soluble and has a high solution viscosity are, in particular, types of raw materials, molar ratios of raw materials, concentrations, addition methods of raw materials, pH, reaction temperature, reaction time, and stability of products. Is important.

As epihalohydrin, epifluorohydrin, epichlorohydrin, epibromohydrin,
Epiiodohydrin or the like is used.

As the dialdehyde, glyoxal,
Malondialdehyde, succinaldehyde, glutaraldehyde, adipaldehyde, maleindialdehyde,
Dialdehydes such as fumardialdehyde are used, but formaldehyde is not preferable because the reaction rate is slow and the product is unstable.

The water-soluble high-polycondensate obtained by reacting a water-soluble 4-aminomethyl-1,8-octanediamine-epihalohydrin polycondensate with a dialdehyde or a salt thereof has a linear aggregation property. Generally, the higher the degree of condensation is, the better it is. Therefore, in synthesizing the polycondensate or a salt thereof, it is important to select reaction conditions that are linear and increase the degree of polycondensation as much as possible.

Reaction molar ratio of 4-aminomethyl-1,8-octanediamine-epihalohydrin polycondensate and dialdehyde when dialdehyde is reacted with 4-aminomethyl-1,8-octanediamine-epihalohydrin polycondensate Is
4-aminomethyl-1,8-octanediamine-epihalohydrin polycondensation raw material of 4-aminomethyl-1,8-octanediamine 1 mol amount of dialdehyde 0.0001 mol amount or more is suitable, dialdehyde is about 0.0001 If the amount is less than the molar amount, polycondensation does not proceed because the dialdehyde is too small with respect to the amine group.

Water is generally used as the solvent, and the concentration of 4-aminomethyl-1,8-octanediamine-epihalohydrin polycondensate is preferably 2% or more. The highly polycondensed product which is a reaction product of highly polycondensed 4-aminomethyl-1,8-octanediamine-epihalohydrin polycondensate and dialdehyde according to the present invention is alkaline and hardly soluble or insoluble in water. Therefore, it is necessary to keep the pH of the liquid at about 10 or less in the polycondensation reaction.

The reaction temperature and the reaction time are important conditions which are related to each other. The reaction rate is slow at low temperatures, and an appropriate temperature is selected below the boiling point.

If the reaction time is too long, it may become insoluble, so it is necessary to select it according to each reaction condition, and it can be easily selected experimentally.

As the reaction time elapses, the liquid becomes viscous, and when polycondensation proceeds excessively, insoluble jelly is produced.

Since the coagulant is added as an aqueous solution at the time of use, the product is stopped and stabilized at a polycondensation degree within the limit of water solubility.

For stabilization, there are a method of diluting, a method of keeping at a low temperature, and a method of adding / reacting lower alcohols, lower amines, lower acids and other compounds having active hydrogen.

The water solubility of the high polycondensate or a salt thereof according to the present invention means that the high polycondensate is water-soluble in the free form or in the form of a salt with an acid or is uniformly dispersible in water. Say.

As the acid for forming the salt, various inorganic and organic acids are used.

The flocculant according to the present invention is used in the following method. For example, a small amount of one or several coagulants according to the present invention is added to raw water and mixed, followed by sedimentation, flotation, screening, and filtration. In this case, inorganic salts, other polymer coagulants and the like may be used in combination. it can.

The high polycondensate or salt thereof according to the present invention is added in an amount of 1 t of a substance to be treated such as a suspended substance of raw water, a coloring substance and a solute.
Approximately 0.5g to 500kg per item, and select an appropriate amount depending on the target.

The polycondensation product of the flocculant or a salt thereof according to the present invention can be mixed with other nonionic / cationic polymer flocculants, inorganic salts, nonionic organic substances, etc., and the solubility is improved. Salts and organic solvents can be mixed in order to increase the viscosity, or for the purpose of adjusting the viscosity and the like.

[0034]

The remarkable flocculating performance of the flocculant according to the present invention is that the water-soluble high polycondensate or salt thereof according to the present invention has a characteristic as a polyvalent cation, and can be stretched at a high degree of polymerization. Aggregates because it is expanded and has less intramolecular loss of active groups, so it is remarkably adsorbing / reactive, reacts electrostatically with anions to form a sparingly soluble salt, and strongly adheres to negative colloid particles. It has a low valency, lowers the electrokinetic potential by using a small amount, and also has a cross-linking effect by adsorbing to coarse particles, and these effects effectively act to form large and stable flocs due to aggregation depending on the object. It is a thing.

[0035]

Next, an embodiment of the present invention will be described. Example 4 Synthesis of high-polycondensation cationic polymer by a method of adding dialdehyde to a solution of 4-aminomethyl-1,8-octanediamine-epichlorohydrin polycondensate and subjecting them to polycondensation reaction In addition, the flocculation performance for these suspensions was tested.

Epichlorohydrin was added to an aqueous solution of 4-aminomethyl-1,8-octanediamine (molar ratio 1: 1).
A polycondensate (concentration: 1%, viscosity: 5.2) was obtained by reaction, and glutaraldehyde was added as an aqueous solution to the starting 4-aminomethyl-1,8-octanediamine at a molar ratio of 1: 0.2. Depending on the reaction method, concentration 1%, viscosity
Ten high polycondensate solutions were obtained.

The obtained cationic high polycondensate was used in an agglomeration experiment on a coal suspension.

Agglomeration test method Coal (ash content: 38.6%) having a particle size of 74 μm or less was prepared, water was added to adjust the concentration to 5%, and the mixture was vigorously stirred and uniformly dispersed.
After standing at ℃ for 1 hour, it was used for aggregation experiments. In this case, the pH of the suspension is 9.0.

The suspension was placed in a settling tube having an inner diameter of 1.28 cm and a length of 30 cm.
20 ml was taken, a drug was added, and the solution was inverted 10 times and allowed to stand still, and the sedimentation velocity at the sedimentation interface in the constant velocity sedimentation region at the initial stage of sedimentation was measured. Further, the upper liquid after standing for 30 minutes was sampled, and the light transmittance at a wavelength of 700 nm was measured. The experiment was conducted at a liquid temperature of 20 ° C.

Results of Aggregation Experiment 4-Aminomethyl-1,8-octadiamine 4-aminomethyl-1,8 obtained by polycondensation reaction of epichlorohydrin
-Octanediamine-epichlorohydrin polycondensate increases the viscosity of the aqueous solution as the polycondensation reaction proceeds, and finally forms jelly and becomes insoluble in water.

Regarding the correlation between the viscosity of the aqueous polycondensate solution and the coagulation performance, the higher the viscosity, the smaller the coagulation value, the higher the sedimentation speed, and the better the coagulation performance. However, the aggregation performance is not improved or deteriorated. Jelly is difficult to mix with the suspension and has almost no aggregation ability.

The decrease in the aggregation performance at high viscosity is due to the linear polymer at low and medium viscosities, whereas at high viscosity there is intramolecular loss of active groups due to grafting and crosslinking, resulting in suspended particles. It is considered that the effect of reducing the surface charge and the effect of cross-linking adsorption due to the adsorption on the surface are reduced.

4-Aminomethyl-1,8-octanediamine-epichlorohydrin polycondensate was mixed with glutaraldehyde in a molar ratio of 1: 0.2 per 4-aminomethyl-1,8-octanediamine as a raw material. When a coagulation experiment was conducted on the high polycondensate obtained by the reaction, the coagulation value, particularly the effect of promoting precipitation, was excellent, and the coagulation value was 0.6 mg / l. This value is the highest performance that has not been obtained with the conventionally known polymerizable / condensation type cationic polymers.

The maximum settling velocity of flocculated flocs was about 22 cm / min. This value is the highest performance that was not obtained with the conventionally known cationic polycondensate, and is equivalent to the currently-produced polymerized methacrylic acid dimethylaminoethyl ester (polydimethylaminoethyl methacrylate) salt or Performance that exceeds that.

The clarity, that is, the light transmittance, was about 80% or more in the above experiments.

In the synthesis of the high polycondensate of this example, malondialdehyde was used in place of glutaraldehyde to synthesize the high polycondensate according to the present invention. Was recognized.

Claims (1)

(57) [Claims] 1. A water-soluble 4-aminomethyl-1,8-octanediamine-epihalohydrin polycondensate containing dialdehyde in a molar ratio of 1: 0.0001 or more per 4-aminomethyl-1,8-octanediamine as a raw material. An aggregating agent comprising a water-soluble high polycondensate or a salt thereof obtained by adding and reacting within the range.